Patent GB-1276011-A (GB)
Title: Improvements in or relating to a clamping device
Inventor: PARRY PAUL
IPC: E05D11/00
Filed: 1969-05-13
Abstract: 1276011 Releasable fastenings disc and socket pivot P PARRY 13 May 1969 [17 May, 1968 26 March 1969] 24353/68 Headings E2A E2B and E2F A clamping device comprises: a first element having a support spindle 9, a second element capable of rotation relative to said first element and having a cylindrical aperture 6 which receives two segments having recesses providing a cylindrical bore 8 adapted to engage said support spindle, said two segments also each having an outer part cylindrical surface biased into clamping contact with the surface of the cylindrical aperture, either (1) a ramp provided by either said first element or one of the segments and a cooperating pin secured either to the one segment or the first element or (2) two ramps provided either by said first element or one ramp by each of the segments and two co-operating pins secured either to respective segments or to the first element, the intraction of the or each said ramp and said corresponding pin, or an element carried by each pin when there are two, being arranged so that a torque which is exerted on the second element in a direction in which clamping is desired and which creates an initial relative rotation of said first and second elements moves the segments to produce an increased clamping action and control means adapted to disengage said segments from said surface of the cylindrical aperture so as to release the clamping action and allow relative rotation of said first and second elements.  In the construction shown there are two ramps 18a, 19a provided by the fixed element 11 and the segments 14 and 16 carry the pins 18, 19 so that relative rotation of the two elements in either direction is opposed by movement of one or other of the segments. The control means 20 is a lever which includes an L-shaped strip 21 which is pivoted to the segment 14 by means of a pin 22a and an aperture 22 the strip has a notch 23 which provides a cam surface cooperating with a pin 24a carried by the segment 16; pivoting the lever causes the two segments to be moved towards each other. The means 17 for biassing the two segments towards each other is a strip 17 which is integral with the two segments so that a ring 7 is formed; in a modification however a spring can be provided disposed in a slot which separates the two segments. As shown the second element 4 is carried by a plate 3 the plate 3 being shown attached to the casement frame of a window with the element 11 being attached to the fixed frame. The fact that the two segments are biassed into clamping contact with the cylindrical wall of the aperture 6 means that when the casement frame 1 is rotated relative to the fixed frame 2, the segments are moved with the frame causing the increase of the clamping action referred to above by the co-action of one or other of the pins 18 or 19 with the appropriate ramp 18a or 19a. In a modification instead of the strip 21 of the lever being sandwiched between the ring 7 providing the two segments and the strip 17, and the element 11, it is disposed on the opposite side of the ring to the element 11 and the element 11 instead of having the ramp carries the two pins 18 and 19 which engage in apertures in the segments which apertures provide the ramps. The lever 20 is also disposed at right angles to the lever of the previous embodiment with the notch 23 being suitably repositioned. This device is stated to be suitable for controlling the angle of the backrest of a vehicle. In a modification the pins 18 and 19 instead of engaging the ramp surfaces directly engage the surfaces through shoes. In another construction described as part of a door latch mechanism the second element is formed with teeth on its periphery which are engageable with a spring loaded keeper and the element 11 is disposed on a bottom of a casing of the mechanism so that the spindle 9 carrying the ring 7 is vertically disposed. Only one of the segments is provided with a ramp and there is only a single pin which is carried by the element 11 so that movement of the element 4 is opposed in only one direction of rotation, i.e. in the direction which would result in opening movement of a door upon which the latch mechanism is mounted. The lever 20 is pivoted on one segment and engages a pin carried by the other and it is connected to a push-pull spindle with handles at each end so that the segments can be moved towards each other for opening the door. In a modification of this construction the pin is carried by one segment and the ramp is provided by the element 11; the lever 20 is then rigidly connected to the other segment so that when the spindle carrying the handles is operated the segment is moved away from the cylindrical surface of the aperture 6. In all the constructions the bore receiving the spindle 9 is disposed eccentrically relative to the partcylindrical surfaces of the segments so that rotation of the ring about the spindle caused by movement of the element 4 causes the segment which is not moved by the coaction of the ramp and pin to be jammed between the pin and the cylindrical wall so that both segments act to stop the rotation.